Novel and Facile Method, Dynamic Self-Assemble, To Prepare SnO₂/rGO Droplet Aerogel with Complex Morphologies and Their Application in Supercapacitors

Abstract

A facile and novel method to prepare SnO₂/reduced graphene oxide (rGO) droplet aerogels with complex morphologies had been developed. This method has been named dynamic self-assemble. Aerogels with both “egg-tart” and “mushroom” shapes were obtained by this method. The changes in the graphene oxide (GO) droplet morphologies during the dynamic process of a GO droplet falling into a SnCl₂ target solution were monitored using a high speed camera. The formed SnO₂/rGO aerogels were then characterized by Raman spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The microstructures of the SnO₂/rGO aerogels were observed with scanning electron microscopy and transmission electron microscopy. Finally, the SnO₂/rGO droplet aerogels were used as the electrode material in a symmetrical two-electrode supercapacitor and the electrochemical performance of the supercapacitor was investigated using cyclic voltammetry and galvanostatic charge/discharge methods. The SnO₂/rGO electrodes demonstrated excellent electrochemical performance and stability. At a scan rate of 5 mV/s, their highest gravimetric and volumetric specific capacitances were 310 F/g and 180 F/cm³, respectively, and their energy and power densities were as high as 30 Wh·kg^–1 and 8.3 kW·kg^–1, respectively